Method for preparing ammonium zirconium sulfate salt



Patented Oct. 10, 1950 UNITED s'm'r'ss PATENT OFFICETJ...

METHOD FOR PREPARING AMMONIUM ZIRCONIUM SULFATE SALT Warren E. Blumenthal, Niagara Falls, N. Y., assi gnor to National Lead Company, New York, N. Y., a corporation of New J crsey No Drawing. Application May 18, 1949, Serial No. 94,057

2 Claims.

to obtain optimum ields which are generally not high. The sulphate product so produced is hard and glassy and is difiicult to remove from reaction vessels. No agent has been found to catalyze this reaction and no success has apparently attended efforts to solve the mechanical problems involved. Fusion of zirconia with alkali bisulphates yields a .water soluble zirconium sulphate but this reaction requires much excess of bisulphate to achieve good yields. In this method, the product is found contaminated with the alkali used in the fusion, which cannot readily be separated. Some success has attended the production of zirconium sulphate by treating zirconium cyanonitride with sulphuric acid.

This process, While producing a soluble zirconium sulphate, suffers from several disadvantages particularly difficulty of grinding the cyanonitride to suitable particle size and the physical difficulties of handling the hardmassive cake whichre- I sults from the reaction. I

This invention, therefore, has for its principal" object the production of water soluble sulphate" salts of zirconium by a simple economical process from. zirconia (ZrOz). this invention to produce a double salt, an ammonium zirconium sulphate according to the formula (NH4) 2H2ZrO(SO4) 3. Another object of the invention is to provide a simple, efiicient method for the production of ammonium zirconium sulphate salt compositions which are substantially water soluble.

This invention, in its broadest aspects, contemplates reaction at elevated temperatures between ammonium sulphate and zirconia (ZrOz) to produce novel soluble ammonium zirconium sulphate salt compositions. Theammonium sulphate and zirconia are individually finelyground and thoroughly mixed together in proportion of from 2 to about 3.5 moles of ammonium sulphate to 1 mole of zirconium oxide. The mixture is heated to between 400 and 600 C. for a sufiicient time for the entire mass of the reactants to attain the desired temperature and then to remain at this temperature for from about 5 minutes to 2 hours. During the heating, the reactants soften to a semi-liquid mass then set to a It is a further object of firm but pulverulent solid. This product is allowed to cool toroom temperature and may then be milled to any desired degree of fineness.

The product is a substantially water soluble zirconium salt composition consisting essentially of combined ammonium, hydrogen, zirconium oxide, and sulphate radicals within the following limits by weight:

Per cent NH4 from 2 to 12 H up to 0.7, ZrO from to S04 from to The starting material in this process may be crude zirconia (Z1 02) which is available as the mineral baddeleyite or as a commercial product; prepared by any one of several well-known processses. The ammonium sulphate raw material; may be of an ordinary commercial grade. Both,

these materials are employed in comminuted. form and preferably should be finely ground, a. fineness of about 325 mesh being suitable; and;

thoroughly intermixed. r

The proportions of the raw materials may vary over a'range of from about 2 to about 3.5 moles.

of ammonium sulphate to 1 mole of zirconium:

oxide.

It is preferred, however, thatthe raw materials be taken so that for each mole of zirconium oxide: there will be present 3 moles of ammonium sul--- phate. Combinations of these proportions of in gredients, are furnaced preferably at a tempera-- ture between 400 C. and 500 C. fora period of between 10 to 40 minutes, to produce a salt containing:

Per cent; NHq. 3.4 H 0.5 ZrO 24.? S04 66 4 and which may be represented by the formula (NH4) 2H2Z1O (S04) 3. reaction in this case proceeds as follows:

The equation represents the observation that ammonia and water are volatilized during the reaction, and a, soluble product of the indicated composition is recovered.

Theterm substantially water soluble. is used in this specification to mean that the reaction product is entirely soluble in water and only impurities remaining from the raw materials constitute a small insoluble contamination which will I not generally exceed 10%. Following the preferred procedure according to this invention a product will be obtained of which dissolves in water.

It is postulated that the heating and length of the heating cycle may obviously be made to produce various compositions as desired.

To produce the preferred composition, that is (NHi) 2H2ZrO(SO4) a it is necessary that the reactants be heated under conditions so that the desired amounts of volatile compounds are lost from the furnace charge. This may be accomplished by heating the finely ground and intermixed reactants in thin layers, preferably between and V thick for. a period of time varying from about 10 to 40 minutes. The optimum temperature for the reaction is about 450 C. and it has been found that below 400 C. and above 600 C. poor yields make the process uneconomical. It is likewise indicated that if the product is heated too long, part of the yield is K ratio is about-3 moles of ammoniumsulphate to:

1 ofraw zirconia.

It is postulated that during thereaction, the

hydrogen in the zirconium acids I-IzZrO(SO4)2 and H4Z1'O(SO4)3 may be partially or wholly replaced by ammonium radicals. During the heating, ammonia, S03, and water may be driven off. in varying amounts to produce salt compositions within the range of analysis indicated, and may contain one or several of these compounds.

In order that this invention may be more clearly understood, the following examples are;

shown:

Example 1 123.2 gm. of a technical grade of zirconiumv oxide, 325' mesh, was mixed thoroughly with 396.4

gm; of a technical grade of ammoniumsulphate. i

The mixture was spreadin layers /4 /2-'- thick in stainless steel trays and held for thirtyminutes in amuflle furnace at.a.temperature..of.4.75f

C. The product was then removed from the furnace, allowed to cool to room temperature,

and pulverized in a hammer mill;

The product was found to consist of the white, water soluble compound (NI-I4) 2H2ZIO(SO4)a together with 5% of insoluble impurities.

Ezramplecz' The product was found to consist of the white 1 water soluble compound (NI-I4)I-I3ZrO(SO4)3'to' v gether with 5%;ofinsoluble-impurities.

4 The percentage composition of the products of Examples 1 and 2 was as follows:

Example 1 Example 2 Per cent Per cent NH 8. 4 4.3 0. 5 0. 7 24. 7 25. 7 66. 4 69. 3

The products of this invention are ammonium zirconium sulphate salt compositions which are substantially pure and white and which may, if desired, be readily converted to other white zirconium chemicals which are useful in manufacturing gas mantles, water-repellents and other products. The ammonium zirconium sulphates form clear, colorless. solutions with water and do not undergo decomposition on boiling. This is an advantage over zirconium sulphate as produced by previously known methods which tends. to hydrolyze to some degree in Water, particularly in dilute solutions, yielding insoluble hydrolysates. The process of this invention is simple, requiring. but a single operation on, the mixtureof raw materials i. e. heating. This results in excellent economy of production. It is both possible and practical to furnace the mixture of raw materials according to this invention in a moving hearth furnace, for instance, and so produce the desired products continuously.

While this invention has been described and illustrated by the example shown, it is not intended to be limited strictly thereto and other modifications and variations may be employed within the limits of the following claims:

I claim:

1. A process for production'of an ammonium zirconium sulphate salt composition which comprises intermixing comminuted sulphate and com-minuted zirconium oxide in proportion so that for each mole of zirconium oxide there are present from 2 to 3.5 molesof a-mmonium, sulphate and heatinggthe so-formed mixture at a temperature of between about 400 and 600 C. for a period of between about 5 minutes to 2 hours.

2. A process for production of an ammonium zirconium sulphate salt composition which. comprises intermixing. comminuted ammonium sulphate and comminuted zirconium oxiderin'proportion so that for each moleof zirconium oxide there are present 3 moles of ammonium. sulphate; and heating the so-formed mixture: at a tem-- perature; of between 400 and. 500 C. for a period: of between about 10 to about 401 minutes. WARRENB; BLUMENTH'AL.

REFERENCES CITED The following references are of record in the file-of this patent:

UNITED STATES PATENTS Number Name Date 1,540,425 Ryan. June.2,. 192.5 2,264,414 Sommerville etral. Dec; 2, 19421 OTHER REFERENCES Mellor: Treatise on Inorganic and Theoretical. Chemistry (1927), vol. 7, page 159.

Gmelin-Krauts: Handbuch des Anor-ganis-f vol. 6-, Part 1 pages 27,,

chen Chemie (1928), 718 and-719.

ammonium 

1. A PROCESS FOR PRODUCTION OF AN AMMONIUM ZIRCONIUM SULPHATE SALT COMPOSITION WHICH COMPRISES INTERMIXING COMMINUTED AMMONIUM SULPHATE AND COMMUNITED ZIRCONIUM OXIDE IN PROPORTION SO THAT FOR EACH MOLE OF ZIRCONIUM OXIDE THERE ARE PRESENT FROM 2 TO 3.5 MOLES OF AMMONIUM SULPHATE AND HEATING THE SO-FORMED MIXTURE AT A TEMPERATURE OF BETWEEN ABOUT 400* AND 600*C. FOR A PERIOD OF BETWEEN ABOUT 5 MINUTES TO 2 HOURS. 